Optical properties of GaN/Al0.2Ga0.8N multiple quantum wells grown with semi-polar (10-11) orientation on patterned 7°-off Si (001) substrates have been investigated. Studies performed at 8 K reveal the in-plane anisotropic behavior of the QW photoluminescence (PL) intensity for this semi-polar orientation. The time resolved PL measurements were carried out in the temperature range from 8 to 295 K to deduce the effective recombination decay times, with respective radiative and non-radiative contributions. The non-radiative component remains relatively weak with increasing temperature, indicative of high crystalline quality. The radiative decay time is a consequence of contribution from both localized and free excitons. We report an effective density of interfacial defects of 2.3 × 1012 cm−2 and a radiative recombination time of τloc = 355 ps for the localized excitons. This latter value is significantly larger than those reported for the non-polar structures, which we attribute to the presence of a weak residual electric field in the semi-polar QW layers.

We calculate the Casimir-Lifshitz pressure in a system consisting of two different one-dimensional dielectric lamellar gratings having two different temperatures and immersed in an environment having a third temperature. The calculation of the pressure is based on the knowledge of the scattering operators, deduced using the Fourier modal method. The behavior of the pressure is characterized in detail as a function of the three temperatures of the system as well as the geometrical parameters of the two gratings. We show that the interplay between nonequilibrium effects and geometrical periodicity offers a rich scenario for the manipulation of the force. In particular, we find regimes where the force can be strongly reduced for large ranges of temperatures. Moreover, a repulsive pressure can be obtained, whose features can be tuned by controlling the degrees of freedom of the system. Remarkably, the transition distance between attraction and repulsion can be decreased with respect to the case of two slabs, implying an experimental interest for the observation of repulsion.

We compare the optical properties of GaN/Al0.15Ga0.85N multiple quantum wells grown on an m-plane (10-10) oriented GaN substrate with those of (1-101)-oriented GaN/Al0.15Ga0.85N multiple quantum wells grown by metal-organic chemical vapor deposition on a patterned (001) 7°-off oriented silicon substrate. The optical properties are studied in 8K-300K temperature range. They reveal strong in-plane optical anisotropies as predicted by group theory. Polarized time resolved temperature- dependent photoluminescence experiments are performed providing access to the relative contributions of the non-radiative and radiative recombination processes. We deduce the variation of the radiative decay time with temperature in the two polarizations. A global comparison of the light emission efficiency in both samples is finally addressed and brought in agreement with the predictions of k.p calculations.

A layered waveguide supported hybrid modes between a surface plasmon and a confined guided mode is studied. The condition for the strong coupling regime are described. The Green function is obtained and decomposed along the continuous and discrete spectrum.

The optical properties of GaN/Al0.15Ga0.85N multiple quantum wells are examined in 8K–300K temperature range. Both polarized CW and time resolved temperature-dependent photoluminescence experiment are performed so that we can deduce the relative contributions of the non-radiative and radiative recombination processes. From the calculation of the proportion of the excitonic population having wave vector in the light cone, we can deduce the variation of the radiative decay time with temperature. We find part of the excitonic population to be localized in concert with the report of Corfdir et al. (Jpn. J. Appl. Phys., Part 2 52, 08JC01 (2013)) in case of a-plane quantum wells. VC 2014 AIP Publishing LLC.

Surface Plasmons (SP) are electromagnetic modes that do exist at the interface between a dielectric and a metal. For metallic particles (spheres, ellipsoids...), such modes are termed localized surface plasmons (LSP). They are at origin of the red colour of Au colloidal solutions and that of the famous Lycurgus cup (Roman glass cup now in the British muséum : it appears red when enlightened from inside and green if fenlightened from outside). Their unique properties (high sensitivity to the environment, extreme confinement, enhanced field strength, fields squeezing...) make them suitable for many applications ranging from chemical and biological sensors to extremely miniaturized optical devices. Furthermore, they play an important role in some recently discovered physical phenomena like "hot spots" on rough surfaces or the extraordinary enhanced transmission through "subwavelength photon sieves". In this talk, I will make a review on SP and LSP with special focus on their applications and I will present our recent research on strong coupling between SPs and optical waveguides.

In this paper we present an extension of the modal method by Gegenbauer expansion (MMGE) [J. Opt. Soc. Am. A 28, 2006 (2011)], [Progress Electromagn. Res. 133, 17 (2013)] to the study of nonperiodic problems. The nonperiodicity is introduced through the perfectly matched layers (PMLs) concept, which can be introduced in an equivalent way either by a change of coordinates or by the use of a uniaxial anisotropic medium. These PMLs can generate strong irregularities of the electromagnetic fields that can significantly alter the convergence and stability of the numerical scheme. This is the case, e.g., for the famous Fourier modal method, especially when using complex stretching coordinates. In this work, it will be shown that the MMGE equipped with PMLs is a robust approach because of its natural immunity against spurious modes.